What is this mode that is causing everything to be evently scaled?
On the top right of your viewport, next to 'Global', you have an icon with 2 circles with dots in them. This means that your transform Pivot point is set to individual origins. Which means that every selected objects/face/edge will be scaled individually. If there is a hotkey for this I don't know it, but you can switch it by clicking on the icon and choosing whatever you want, by default Blender set it on Median.